1. Field of the Invention
The present invention relates to a liquid crystal display and fabricating method thereof, and more particularly to a method enhancing sealing of the liquid crystal display.
2. Description of the Related Art
Liquid crystal display (LCD) is a commonly used flat panel technology. Owing to dielectric anisotropy and conductive anisotropy of liquid crystal molecules, molecular orientation of liquid crystals can be shifted under an external electronic field, such that various optical effects are produced.
An LCD panel is generally made up of two substrates, with a gap preserved therebetween, and a liquid crystal layer filled within the gap. Respective electrodes are formed on the two substrates, respectively, to control the orientation and shift of liquid crystal molecules.
A TFT (thin film transistor) LCD panel is generally made up of a TFT array substrate and a color filter substrate. The two substrates are first manufactured separately, then aligned and joined together. During the combining of the two substrates, generally referred to as cell process, spacers are spread over the liquid crystal chips to maintain and even the cell gap between the two substrates, and a seal pattern is formed along the periphery of each liquid crystal chip to adhere the two substrates after curing, sustaining the two-layered unit. Afterwards, the two-layered unit is broken to divide each liquid crystal chip into an independent double-layered unit, having a notch therebetween for liquid crystal injection. The notch is then sealed after injection of liquid crystals to complete the fabrication of the LCD panel.
The sealant applied in the current cell process for LCD can be, for example, epoxy or polyacrylate, first in a fluid state, and then thermally-cured or photo-cured to complete sealing. In the cell process of a large-scale LCD panel, a step of applying uniform pressure on the two substrates is usually performed, between the injection of liquid crystals and sealing of the notch, to spread the liquid crystals uniformly, expel the redundant material, and create a slight pressure therein, drawing the sealant into the notch in the subsequent step, enhancing the permeating rate of the sealant, and assuring sufficient permeating depth thereof. In the cell process of a small-scale LCD panel, however, applying a similar step for each small panel is time-consuming, thus the notch is usually sealed directly after the injection of liquid crystals. Owing to the absence of the slight pressure within the double-layered unit, the sealing time or length of sealant application must be prolonged to compensate for the slowdown of permeating rate.
Further, polymeric material is used in the cell process as a sealant because of its resistance to environmental effects, chemicals, and adhesion, but peeling or bubble formation may occur after curing the sealant, if improper sealant, curing temperature, or curing time is applied.